class Solution {
public:
    bool containsDuplicate(vector<int>& nums) {
        unordered_map<int, int> countMap;
        for(auto e : nums)
        {
            countMap[e]++;
        }


        for(auto& kv : countMap)
        {
            if(kv.second != 1)  return true;
        }


        return false;
    }
};
